Prawo Zamówień Publicznych no. 4/2022 Jubileusz Krajowej Izby Odwoławczej Kilka uwag na 15-lecie działalności Krajowej Izby Odwoławczej Jan Kuzawiński Cooperation between the National Appeal Board and the CJEU Aleksandra Sołtysińska On the need for further improvements in the appellate procedure before the National Appeal Board Agnieszka Trojanowska, Bartosz Stankiewicz Estimation of construction costs in public procurement in the current legal situation Andrzej Borowicz Withdrawal from a construction works contract concluded under the public procurement procedure Marcin Czerwiński On certain new public procurement law procedures Włodzimierz Dzierżanowski Some problems concerning exclusion of a contractor because of improper performance of the previous public contract Franciszek Łapecki Nullification of concession proceedings Łukasz Górnicki Principles of describing the subject of a construction contract in the light of the new legal regulation Marta Cichalewska The offence of obstructing a public contract award proceedings after the amendment of Art. 303 of the Penal Code Michał Makowski Grounds for reserving contractual penalty vs the object of a public contract. Gloss of the judgments of the National Appeal Board of 22 September 2021 (KIO 2340/21) and of 23 November 2021 r. (KIO 3277/21) Wojciech Robaczyński